That explains why Manuel barely blinked yesterday at news that Oliver Perez’s hugely disappointing season is officially over because of recurring tendinitis in his right knee.

Coming less than 24 hours after the Mets lost ace Johan Santana and setup man J.J. Putz for the rest of this cursed season, the news that Perez will require season-ending surgery caused Manuel to do the only thing he can do — look ahead.

“We’ve got to get all these things out of the way,” Manuel said before last night’s 5-3 loss to the Marlins. “This is the year for this to happen. We’ve got to get it done and move forward, and hopefully, we’ll have some healthier days coming.”

The Mets said Perez is expected to make a full recovery in time for spring training, and right-hander Lance Broadway — obtained from the White Sox in the Ramon Castro trade — was called up from Triple-A Buffalo to take Perez’s spot on the roster. Left-handed reliever Pat Misch is likely to take Perez’s next start tomorrow against the Cubs in Chicago.

Perez becomes the 13th player on the Mets’ current disabled list, and the club has a whopping $88 million committed to those players.

Perez’s departure leaves Mike Pelfrey as the last original man standing in the Mets’ rotation, and the big right-hander wasn’t up to the task here yesterday in the Mets’ fifth consecutive loss.

Pelfrey (9-9) gave up all five runs on 11 hits and five walks in just 5 2/3 innings as the Mets fell despite some early success against Marlins ace Josh Johnson (13-3).

But the bigger story was Perez’s scheduled surgery, which resulted from an exam yesterday by team Dr. David Altchek at the Hospital for Special Surgery and brought an abrupt erupt end to Perez’s disastrous season.

Perez, who turned 28 earlier this month, finished the season 3-4 with a 6.82 ERA in 14 starts. Pitching coach Dan Warthen said the injury and the terrible numbers were related.

“I think [the knee] has been a factor all year long,” Warthen said. “We’ve never seen Oliver throw a ball over 91 or 92 miles an hour at any time. That knee really [bothered] him after 45 or 50 pitches every time out.”

The loopy left-hander always has been an underachiever, but this year was by far Perez’s worst because the Mets and general manager Omar Minaya gambled in the offseason by giving him a three-year, $36 million contract.

That gamble backfired when Perez showed up out of shape in spring training, struggled for Team Mexico in the World Baseball Classic, then stumbled badly out of the gate for the Mets in April.

Perez’s start was so bad that the Mets yanked him from the rotation after a dreadful outing May 2 in Philadelphia, suddenly citing the previously undisclosed knee problems, and he didn’t return until July 8.

Perez had his moments over the past two months but was mostly a washout before aggravating the knee problems covering first base Aug. 18 at Citi Field against the Braves. What would be Perez’s last start also was his nadir as Manuel yanked him after just two-thirds of an inning last Sunday at home against the Phillies after he gave up six runs and reached a 3-0 count against mentor Pedro Martinez.

According to Manuel, the knee pain kept Perez from getting in good condition, which in turn hampered his performance. Now that the knee problem seemingly is being resolved, Manuel said he is confident Mets fans will see an improved Perez in 2010.

“I think he’ll be fine,” Manuel said of next season. “There’s no doubt in my mind — I think he’ll be fine.”